PB2431: OUTCOME OF HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR SEVERE APLASTIC ANEMIA IN PEDIATRIC POPULATION - A SINGLE CENTER EXPERIENCE FROM PUBLIC HOSPITAL
Authors: Rajesh Patil, Ratna Sharma, Pranoti Kini, Amit Jain, Ashutosh Walawalkar, Krunal Shah, Poulami Das, Kalyani Patil, Nidhi Mehta, Santosh Khude, Mamta Manglani
Journal: HemaSphere (2023)

Topic: 22. Stem cell transplantation - Clinical Background: Management of children with severe aplastic anemia (SAA) is challenging in developing world due to diagnostic delays, infections, limited response to immune suppression therapy. Hematopoietic stem cell transplant (HSCT) is a curative treatment in SAA, but its use is limited due to cost involved and nonavailability of HLA matched donors. Aims: To analyse outcomes and challenges encountered during stem cell transplants for pediatric severe aplastic anemia. Methods: This is retrospective analysis of children with severe aplastic anemia who underwent allogenic stem cell transplants at our center from June 2018 till Jan 2023. Patients were considered to have high risk aplastic anemia if they had any of the following: 1. Time to transplant from diagnosis more than 3 months 2. Received more than 20 transfusions before transplant 3. Had previous exposure to ATG 4. Had active infection at the time of transplant. Results: This analysis included 28 patients. 27/28 (96.4%) patients were of high risk category. Median follow up is 1094 days (30 days -1686 days).Median age at transplant was 11years (2 years to 18 years) with male: female ratio of 3:1. Matched related peripheral blood stem cell transplants (MRD) were performed in 20/28 (71.4%) patients, matched unrelated donor (MUD) transplants done in 2/28 (7.1%) patients while 6/28 (21.4%) patients underwent haploidentical stem cell transplants. Fludarabine, cyclophosphamide with or without ATG (FLU CY ± ATG) used as a conditioning regimen for matched related donor transplants while FLU CY ATG was used in MUD transplants. One antigen mismatch or haploidentical stem cell transplant were done using John Hopkins protocol (FLU low dose CY ATG 4Gy TBI). Peripheral blood stem cells (PBSC) was used as stem cell source in all patients. In matched transplants cohort (Both MRD & MUD), all patients had successful engraftment while 5/22 (22.7%) patients had secondary graft failure. Grade II-IV acute GVH was seen in 20% while chronic GVH seen in 10 % patients (only limited type). Event free survival (EFS) and overall survival (OS) is 77.2 % (17/22) in this cohort. In haploidentical stem cell transplant patients, 2/6 (33.3%) patients has primary engraftment failure while there was no secondary graft failure. Grade II-IV acute GVH was seen in 50% while chronic GVH not noticed in any patient. Event free survival (EFS) and overall survival (OS) is 66.6 % (4/6) in this cohort. Cause of death was infections following graft failure in both the cohorts. Summary/Conclusion: Hematopoietic stem cell transplant is an efficacious strategy in treatment of severe aplastic anemia in pediatric population. The outcomes are better in transplant with MRD/MUD donors compared to haploidentical stem cell transplant. Better strategies are needed for prevention and salvage of patients with graft failures thereby improving outcomes in children with aplastic anemia.Keywords: Allogeneic hematopoietic stem cell transplant, Pediatric, Aplastic anemia